This application claims the priority of German Patent Application No. 197 23 647.2, filed Jun. 5, 1997, which is incorporated herein by reference.
1. Field of the Invention
The invention refers to a resettable display of a device for metered administration of a fluid drug, comprising a housing, a fluid container provided in or on the housing and containing the fluid, an actuating device shiftably mounted by a length in or on said housing, which actuating device shifts upon actuation a piston in the fluid container in order to displace from the fluid container a fluid dose adjusted by means of the actuating device, a display provided in or on said housing displaying a measure for the adjusted fluid dose, and a resetting means shifted with the actuating device and thus resetting the display, in which the display comprises a minimum of one counter ring rotated when adjusting the fluid dose from the actuating device in relation to the housing from a zero position, and said resetting means mechanically transfers a shift movement of the actuating device into a reverse rotary movement of the counter ring towards its zero position.
2. Description of the Related Art
A device for the administration of a metered fluid drug is, for instance, known from EP 0 581 925 B1. It is an injection device having the shape of a so-called pen by which a patient can inject himself personally doses of a fluid drug at any time, in particular insulin, to be selected by the patient. The injection equipment comprises an LCD display for display of the fluid drug dose preset by the patient for the next injection. During injection, the display is automatically reset to zero, therefore always displaying the preset fluid dose to be administered for the next injection.
An injection device comprising a mechanical display is known from EP 0 554 996 B1. The preset fluid dose is displayed by two counter rings, a units counter ring and a tens counter ring, provided with suitable scales in order to display the dose preset by the patient in a display window in the housing of the injection device. The display, however, must be reset by the patient after each injection by manually reversing the rotation of the metering and actuating push-button by which the injected fluid dose has been previously preset.
It is the object of the invention to provide a simple, low-priced, resettable display for a device for metered administration of a fluid drug, which is reset automatically when actuating the device in the course of fluid administration, to a preset position, preferably zero.
This object is achieved by a resettable display of a device for metered administration of a fluid drug, comprising a housing, a fluid container provided in or on the housing and containing the fluid, an actuating device shiftably mounted by a length in or on said housing, which actuating device shifts upon actuation a piston in the fluid container in order to displace from the fluid container a fluid dose adjusted by means of the actuating device, a display provided in or on said housing displaying a measure for the adjusted fluid dose, and a resetting means shifted with the actuating device and thus resetting the display, in which the display comprises a minimum of one counter ring rotated when adjusting the fluid dose by means of the actuating device in relation to the housing from a zero position, and said resetting means mechanically transfers a shift movement of the actuating device into a reverse rotary movement of the counter ring towards its zero position. The use of a counter ring and its mechanical resetting by the resetting means constitutes a rather simple, robust solution for resetting the display.
The device for metered administration of a fluid drug is preferably a portable injection device, in particular a so-called pen. However, the invention may also be advantageously used for stationary dosing devices and devices for administration both by injection and infusion. It is applicable to manually operated devices and also to devices operated by driven pumps. Also it may be beneficial when using pipettes.
Compulsory reverse rotation of the counter ring is preferably effected continuously, i.e. only at the end of the shifting movement of the actuating device. When mechanical transferral of the shifting movement of the actuating device is effected simultaneously with the shifting movement effecting the administration of a fluid, i.e. only at reverse shift of the actuating device, only partial administration of the preset fluid dose can be displayed by partial reverse rotation of the counter ring. If this is unimportant in application, however, shift of the actuating device may be effected during reverse shift after completion of fluid administration.
The shifting movement of the actuating device is preferably transferred by a coulisse or like a coulisse into rotation of the counter ring. The coulisse is formed by a guide track and an engaging means compulsorily guided along the guide track during the shift of the actuating device. The coulisse is preferably designed as a pure slideway, but may also be effected in principle by a rolling movement of the engaging means.
Preferably, the engaging means is firmly connected to the counter ring and the guide track is formed on the resetting means. The guide track may, however, also be formed on the counter ring, preferably on one of the internal circumferential areas of the counter ring, thus allowing in this case firm connection of the engaging means with the resetting means or being formed by the same and being shifted together with the actuating device.
In a preferred embodiment, in which the guide track is formed on said resetting means, the resetting means is of a sleeve-type shape. In the following, it is therefore designated a resetting sleeve. The guide track projects over the surface area of the resetting sleeve.
The rotating axis of the counter ring is preferably formed by its center axis, with the counter ring center axis coinciding with the longitudinal center axis of the actuating device, extending in the direction of shift movement. The counter ring encloses the actuating device coaxially. When reversing the rotation of the counter ring, the guide track is pushed into the annular space between the actuating device and the counter ring. In this design, the engaging means projects radially into the interior, preferably in the shape of a simple cam, from the internal circumference of the counter ring. In principle, the longitudinal center axis of the counter ring and therefore its rotary axis may, however, also be arranged vertically to the shifting direction of the actuating device. A cam projecting, for instance, from one of the faces of the counter ring could be compulsorily guided in a guide track formed as a curved segment with reference to the shifting direction of said actuating device, thus initiating reverse rotation of the counter ring.
The display preferably comprises a minimum of two counter rings, one of which displaying the preset basic dose units and the other displaying the number of complete revolutions of the units counter ring. One complete rotation of the units counter ring preferably corresponds to the setting of ten basic dose units, with one scale division on the tens counter ring corresponding to ten of the said basic dose units each. A display based on a system of tens is particularly user-friendly.
Driving a minimum of one and/or a minimum of two counter rings is preferably effected in the same way as in a mileage counter via a shaft extending parallel to the central longitudinal axis of the counter ring and/or counter rings. This results in a particularly simple and robust drive system which can be used as such without the resetting mechanism and/or the counter rings according to the invention. When used in common injection pens, for instance, the display driven by the principle of a mileage counter offers the advantage that it may be used in this application by incurring very low costs for adaptation.
The units counter ring is rotatable and longitudinally shiftable in relation to the actuating device. It may also be connected to the actuating device non-rotatably but able to be longitudinally shiftable in relation to the actuating device.